1) Field of the Invention
The present invention relates to a transmission system for a vehicle, particularly a tractor.
2) Description of the Prior Art
A known transmission system for a tractor is disclosed, for example, in Japanese Laying-Open Publication (Kokai) No. 57-104039. This transmission system comprises a PTO line input shaft directly coupled to a flywheel operatively connected to an engine, and a tubular propelling line input shaft mounted on the PTO line input shaft and coupled to and uncoupled from the flywheel by a dry type frictional clutch. A wet type oil clutch device for effecting backward and forward drive switching and high and low speed range switching is connected to the propelling line input shaft at a position closer than other propelling drive change speed devices are to the engine.
In the above transmission system, generally, a wet type oil clutch is connected to the PTO line input shaft for effecting change speed on the drive through the PTO line. Since the oil clutch is expensive, there is a desire to exclude the oil clutch from the PTO line.